Cylinder for fluid pump motor and the like and method of making



May 26, 1970 s. K. SMITH 3,514,238

CYLINDER FOR FLUID PUMP MOTOR AND THE LIKE AND METHOD OF MAKING FiledSept. 16, 1968 2 Sheets-Sheet l 53 B 53C A l I INVENTOR STANLEY K.-SMITH ATTORNEY May 26, 1970 s. K. SMITH 3,514,238

CYLINDER FOR FLUID PUMP MOTOR AND THE LIKE AND METHOD OF MAKING FiledSept. 16, 1968 2 Sheets-Sheet 2 INVENTOR STANLEY K. SMITH ATTORNEYUnited States Patent 3,514,238 CYLINDER FOR FLUID PUMP MOTOR AND THELIKE AND METHOD OF MAKING Stanley K. Smith, Baltimore, Md., assignor toThe Black and Decker Manufacturing Company, Towson, Md., a corporationof Maryland Filed Sept. 16, 1968, Ser. No. 760,036 Int. Cl. F04c 1/00;F04b 21/08; F01c 1/00 U.S. Cl. 418-153 6 Claims ABSTRACT OF THEDISCLOSURE There is disclosed herein a fluid powered, rotary devicewhich includes a cylinder having a vane carrying rotor rotatablydisposed therein. Pressurized fluid is admitted to the cylinder and actson the vane or vanes causing the rotor to turn and the vane or vanes toride along the inner wall of a cylinder liner. The liner has a novelconstruction formed in a novel manner which contributes significantly toits useful life and efficiency, its physical prop erties, and enhancesthe overall performance of the device.

SUMMARY OF THE INVENTION The present invention is directed to a novelcylinder liner for use in a fluid operated, rotary motor, pump and thelike and to a novel method of making the same.

The liner encases a rotor which has one or more vanes O slidably carriedthereon and, during use, the vane or vanes slide around the inner linerwall. The liner is constructed of a synthetic formable material and isreinforced with a thread or threads wound therethrough and which areconstructed from a relatively hard material which is relativelynon-moisture absorbing and has a low coefficient of friction. Desirably,the threads are spirally wound through the liner in opposite directionson opposite sides of a radial plane substantially bisecting the liner,and the novel forming method disclosed provides for this spiraled,crisscross arrangement. The basic, reinformed liner constructionincreases the dimensional stability thereof and the output of the deviceand contributes significantly to its life. The spiraled arrangement ofthe reinforcing threads has the advantageous effect of equalizing endloading on and centering the rotor vanes.

Main objects, therefore, of the present invention are to provide a novelcylinder liner construction for use in a rotary fluid handling device,such as a motor, pump and the like which liner has superior dimensionalstability and which provides superior performance characteristics andgreater expected life.

Further important objects of the invention are to provide a novelcylinder liner construction of the above character which develops equalend loading on and centers the rotor vanes disposed therein, which iscompatible with existing constructions and which is reliable in use.

Additional objects are to provide a novel method of making a novelcylinder liner construction of the above character which method isrelatively inexpensive to perform, which is reliable and which providesconsistent results.

Other objects and advantages of the present invention will become moreapparent from a consideration of the detailed description to followtaken in conjunction with the drawings annexed hereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view, partly in elevationand partly in section, illustrating a pneumatic motor device embodyingthe liner of the present invention;

3,514,238 Patented May 26, 1970 FIG. 2 is an enlarged view of a portionof the liner of FIG. 1 shown with the rotor removed;

FIG. 3 is a sectional view of FIG. 2 taken along the line 3-3 thereof;and

FIG. 4 is a schematic illustration of a method of making the liner ofFIGS. 13.

BROAD STATEMENT OF THE INVENTION Broadly described, the presentinvention relates to a fluid handling, rotary device comprising acasing, a cylinder including a generally cylindrical liner fixed withinsaid casing, end plate means on opposite sides of said liner, a rotorsupported for rotation within said liner between said end plate meansand having at least one slidable vane adapted to engage the innersurface of said liner during rotation of said rotor, said liner beingconstructed from a synthetic formable material reinforced with threadmeans wound therethrough, said thread means being constructed of arelatively hard material having relatively low moisture absorbing andfriction coeflicient properties.

In another aspect, the present invention relates to a rotary motor, pumpand the like comprising a casing, end plates fixed to said cylinder, acylinder including a generally cylindrical liner fixed within saidcasing, a rotor supported for rotation within said liner and having atleast one slidable vane adapted to engage the inner surface of saidliner during rotation of said rotor, said liner being constructed from asynthetic formable material reinforced with threads wound therethroughand around said liner, said threads being wound in spiral fashionstarting at opposite ends of said liner and crossing at substantiallythe axial center thereof, whereby to generate substantially equal andopposite axial forces on said at least one vane during rotor rotation tocenter said vane between said end plates.

DETAILED DESCRIPTION Referring now specifically to the drawings, apneumatic powered, portable die grinding tool embodying the presentinvention is illustrated generally at 11 in FIG. 1. It will beunderstood, however, that this tool is exemplary only and that theprinciples of the invention apply generally to the class of rotary type,fluid handling devices which include pumps, motors and the like,pneumatic, hydraulic or otherwise and whether they are of the portableor stationary variety.

With this in mind, the die grinder 11 is seen to include a hollow,generally cylindrical motor casing 13 having a spindle housing 15secured thereto. A rotary pneumatic motor 17 is disposed within thecasing 13 and is adapted to impart rotary movement to a spindle 19 towhich a grinding wheel (not shown) may be attached. The motor 17 ispowered by pressurized air admitted through an inlet conduit 21 andcontrolled by a lever 23 and valve plunger 25.

The motor 17 is seen to include a generally cylindrical housing 27 fixedwithin the casing 13 and having a cylindrical liner 29 fitted therein. Arotor 31 within the liner 29 has stub shafts 32, 34 rotatably supportedby bearings 33, 35 within the housing 27 and has one or more radiallyextensible vanes carried thereby. A pair of end plates 38, 49 are fixedwithin the cylinder housing 27 to either side of the rotor 31.

In use, pressurized air entering through the conduit 21 passes into apassageway 39 formed between the housing 27 and the liner 29 and flowsinto the liner 29 by way of ports 41. This air impinges upon one side ofthe vane or vanes 37 causing the rotor 31 to turn and centrifugal forceon the vanes 37 causes them to slide around the inner surface of theliner 29. Air exits the liner 29 and the housing 27 by way of dischargeopenings 43, 45 therein and passes into a pasageway 7 formed between thecasing 13 and the housing 27. From there, air passes through passages 49and exits the front or left-hand end of the spindle housing 15.

It will be appreciated that friction between the outer, longitudinaledge of the vane or vanes 37 and the inner surface of the liner 29 andbetween the lateral or transverse vane edges and the end plates 38, 40affects the speed and output of the device and, in addition shortens thelife of the vanes 37. A novel vane construction, disclosed and claimedin the copending application of William S. Brucker, Ser. No. 575,887,filed Aug. 29, 1966, now Pat. No. 3,417,664, granted Dec. 24, 1968, to agreat extent has obviated this problem by providing a dimensionallystable vane construction having a reduced coefficient of frictionthereby making pOssible closer tolerances, reducing friction, increasingoutput and extending life. The present invention attacks the problemfrom another aspect, namely, by building greater dimensional stabilityinto the cylinder liner and lowering its coefficient of friction. Inaddition, this invention provides a centering action on the rotor vaneswhich further reduces friction and increases the efficiency of thedevice.

Thus, as seen best in FIGS. 2 and 3, the cylinder liner 29 isconstructed from a formable, synthetic material and has thread .meanswound therethrough. The particular material chosen for the liner 29depends to a great extent upon the physical characteristics required inthe particular installation. In a number of pneumatic motorinstallations, for example, the general class of phenolics has beenfound to be satisfactory.

The thread means preferably includes one or more continuous threads, 51,53 wound through the liner material in spiral fashion in oppositedirections on opposite sides of a radial plane substantially bisectingthe liner 29. One way of doing this is to wind the threads 51, 53starting at opposite ends of the liner 29 to cross over each othersubstantially at or near the center thereof. In the embodiment shown inFIGS. 2 and 3, there are three of threads 51, namely 51A, 51B and 51C,and three of threads 53, namely 53A, 53B and 53C. The threads 51A, 51B,51C are wound in spiral fashion from the left-hand end of the liner 29while the threads 53A, 53B, 53C are wound in spiral fashion (opposite tothat of threads 51A, 51B, 51C) starting from the right-hand end of theliner 29. These threads 51, 53 meet and cross over each other atsubstantially the center of the liner 29 and preferably continue on outto the rightand left-hand ends, respectively, of the liner 29 as shownin FIG. 2. It will be appreciated that the liner thickness will bedetermined by the layers of wound threads 51, 53 so that if a thickerliner 29 is desired the threads 51, 53 may be wound back over themselvesas many times as necessary.

The threads 51, 53 are desirably constructed from a relatively hardmaterial which is relatively non-moisture absorbing and has a lowcoeificient of friction. For example, threads made of glass, graphite oralumina fiber have been determined to be satisfactory. In addition tothe desirable physical characteristics these materials possess, theywill not melt at the curing temperatures of phenolics so that theypermit forming of the illustrated liner 29.

In use, the rotor 31 turns about an axis passing through the bearings33, 35 and the vane or vanes 37 ride around the inner wall of thecylinder liner 29. The threads 51A, 51B, 51C and 53A, 53B, 53C presentexposed surfaces to the vanes 37 as they ride around the liner 29. Thespiral arrangement of the threads 51A, 51B, 51C and 53A, 53B, 53C has atwofold purpose: first, each of the exposed thread surfaces sweepsacross the outer edge of the vanes 37 so that this edge of each vane 37is polished thereby reducing friction between the vanes 37 and the liner29 as well as pressure losses past the vanes 37. The threads, beingconstructed of a relatively hard material having a low coetficient offriction further reduces friction so that the efiiciency and output ofthe device is maximized and the problem of heat dissipation isminimized. Second, the spiral arrangement of the threads 51A, 51B, 51Cand 53A, 53B, 530 generates forces on the vane or vanes 37 in a lateraldirection. The opposed spiral arrangement disclosed, wherein the threads51 are inclined at substantially the same but opposite angle from thethreads 53, develops opposing forces which substantially cancel oneanother thereby elfectively centering the vane or vanes 37 between theend plates 38, 40. This is beneficial again because it reduces frictionbetween the vanes 37 and end plates 38, 40 and enhances the efliciencyof the device.

Still another and related advantage lies in the fact that the resistanceto moisture absorption and dimensional stability of the threads 51A,51B, 51C and 53A, 53B, 53C renders the liner 29 similarly dimensionallystable. Thus, expansion of the liner 29 during use is minimized and thedistance between the end plates 38, 40 remains substantially constant sothat the vanes 37 can be dimensioned to close tolerances with respect tothe axial length of the liner 29. This further reduces losses in thedevice and enhances its efficiency.

A novel method used to from the novel liner of the present invention isillustrated in FIG. 4. Here, the cylinder liner 29 is shown as beingformed on a rotating mandrel 101. The threads, there shown to be five innumber, are supported on bobbins 103, 105, respectively, which areadapted to be reciprocated along guide rails 107, 109, as shown by thearrows. The number of threads 51, 53 may vary from one of each up to anyreasonable number, according to particular desires and it will beappreciated that with more threads, the angle each makes with a radialplane through the liner 29 is greater as is the centering forces on thevanes 37. In any event, the threads 51, 53 are fed through baths 111,113 containing the liquid liner material, e.g. phenolic, and arespirally wound on the mandrel 101 starting from axially spaced positionsthereon and progressing toward each other. The threads 51, 53 cross overeach other at a midpoint and are wound on top of one another as shownback out to the starting point. The process may be repeated for as manythread layers as desired according to the desired liner thickness. Theresultant product is then cured or otherwise treat d to cause the linermaterial to set up.

By the foregoing, there has been disclosed a novel cylinder liner forrotary fluid handling devices and a novel method of making said linercalculated to fulfill the inventive objects hereinabove set forth, andwhile a preferred embodiment of the present invention has beenillustrated and described in detail, various additions, substitutions,modifications and omissions may be made thereto without departing fromthe spirit of the invention as encompassed by the appended claims.

'I claim:

1. A fluid handling, rotary device comprising a casing, a cylinderincluding a generally cylindrical liner fixed within said casing, endplate means on opposite sides of said liner, a rotor supported forrotation within said liner between said end plate means and having atleast one slidable vane adapted to engage the inner surface of saidliner during rotation of said rotor, said liner being constructed from asynthetic formable material reinforced with thread means woundtherethrough, said thread means being constructed of a material selectedfrom the group consisting of glass, alumina and graphite fiber and beingrelatively hard and having relatively low moisture absorbing andfriction coeflicient properties.

2. A device as defined in-claim 1 wherein said thread means includesthreads wound in spiral fashion in opposite directions on opposite sidesof a radial plane substantially bisecting said liner, wherebysubstantially equal and opposite axial forces are generated on said atleast one vane during rotor rotation to center said vane between saidend plate means.

3. A device as defined in claim 1 wherein said synthetic formablematerial is a phenolic material.

4. A rotary motor, pump and the like comprising a casing, a cylinderincluding a generally cylindrical liner fixed within said casing, endplates fixed to said cylinder, a rotor supported for rotation withinsaid liner and having at least one slidable vane adapted to engage theinner surface of said liner during rotation of said rotor, said linerbeing constructed from a synthetic formable material reinforced withthreads wound therethrough and around said liner, said threads beingwound in spiral fashion starting at opposite ends of said liner andcrossing at substantially the axial center thereof, whereby to generatesubstantially equal and opposite axial forces on said at least one vaneduring rotor rotation to center said vane between said end plates.

5. A device as defined in claim 4 wherein said threads are formed ofmaterial selected from the group consisting of glass, alumina andgraphite fiber.

6. A device as defined in claim 4 wherein said threads include aplurality of continuous threads wound at substantially the same butopposite angle on opposite sides of the liner axial center.

6 References Cited UNITED STATES PATENTS 2,487,449 11/1949 Knudson103-136 2,614,058 10/1952 Francis 156175 5 2,747,616 5/1956 Gunahl156175 2,843,153 7/1958 Young 156175 2,925,786 2/1960 Hill 103-2162,961,903 11/1960 Roggenburk 91-121 10 3,417,664 12/1968 Brucker 103-216FOREIGN PATENTS 855,672 2/ 1949 France. 394,495 6/ 1933 Great Britain.

HENRY F. RADUAZO, Primary Examiner US. Cl. X.R.

